How do I download information stored in my Chrome extension? - google-chrome

Question

I am developing a Chrome extension where the workflow looks like:
user browses the internet and can save links. I have a strong preferences to store all links locally instead of, say, having to talk to an external server.
user can then hit a button in the extension which generates and downloads a csv file of all the saved links so far
Two questions:
What is the appropriate way to store this data over multiple sessions?
What is the appropriate way of generating the file and prompting a download?
For 1, I plan on using chrome.storage.local.
For 2, it's unclear what the best way is. I'm considering writing the data to options.html or popup.html, then calling chrome.downloads to download that page, but it feels like a massive hack.
What is the correct way of doing 1 and 2?

Answer 1

Using chrome.storage.local is the right way here.
I am using this snippet right from the popup in order to save text/json/csv files:
/**
* #param data {String} what to save
* #param extension {String} file extension
*/
function saveFile(data, extension = 'json') {
const fileName = `export-file.${extension}`;
const textFileAsBlob = new Blob([data], {type: 'text/plain'});
const downloadLink = document.createElement('a');
downloadLink.download = fileName;
downloadLink.href = window.URL.createObjectURL(textFileAsBlob);
downloadLink.target = '_blank';
downloadLink.click();
return fileName;
}
It will save a file to disk. And it is not a hacky way.
Update for #2
Another way is to pass base64 URL to the downloads API:
chrome.downloads.download({url: 'data:image/gif;base64,SEVMTE8gV09STEQh', filename: 'test.txt'})